有機催化劑在不對稱親核取代反應與動力學分割之探討

Abstract

本篇論文利用有機催化動力學分割活化nitroallylic acetates 56a-h，以及2-甲基-1,3-雙酮環戊烷55，進行SN2反應，產生具有掌性分子之產物65a-h，同時具有較高的鏡像超越值(90% ee)，產物65產率(41%)，以及回收起始物56產率(46%)，但鏡像超越質略低(20% ee)。 利用本實驗室所發展之有機催化劑，具有樟腦分子以及咯啶架構之官能基，進行一系列條件之篩選之後，在室溫下，於氯仿(chloroform)為溶劑，反應6小時，可得到最佳結果，此產物為65b之結構，其絕對立體組態由X-射線繞射分析確定。This dessertation deals with the organocatalytic kinetic resolution of activated nitroallylic acetates 56a-h and 2-methylcyclopentane-1,3-dione 55 via SN2 reaction to produce chiral products 65a-h with a high enantiomeric excess (up to 90% ee) and a moderate chemical yield (41%) and acetates 56a-h was recovered obtained with high chemical yield (46%) ，but with a low enantiomeric excess (20% ee). Exclusive screening of various organocatalyst in our laboratory led to the conclusion that pyrrolidinyl-camphor based bifunctional organocatalyst catalyses the reaction at room temperature with in 6h in CHCl3. The structure of the product was fully characterized and the absolute configuration of product 65b was further unambiguously determined by single-crystal X-ray analysis.